The Indian industries have seen and experienced a variety of electronic power transmission products over a period of time. Indeed it has changed a lot on the positive side of Indian industries through industrial automation to energy saving. Today, right from the bottling industries to cement, sugar, chemical, fertiliser, pharmaceutical, engineering or any kind of industry the AC variable speed drives play a vital role whether for automation, energy saving and ultimately cost saving. The structure of the supplier industry for AC drives in India has undergone for a massive change during the last 15 years. Three or four major companies in India controlled the market of AC drives during 1980s. Today, the situation has changed drastically due to the entry of European, American and Japanese companies through their different kind of AC drives ranging from fractional HP rating to HT drive. Whisper is quietly - technically, variable speed drives are becoming more and more alike! Few manufacturers felt comfortable discussing this trend, and some would even seek to deny its truth. But take a look at the facts: AC drives are displacing their DC counterparts in all but most of the specialist applications, so the traditional AC/DC divide has already virtually disappeared. Modern inverter drives invariably incorporate flexible microprocessor control systems, which means that successful features offered by one manufacturer can soon be copied by others. Differences, such as the power technology used by different suppliers are largely transparent to users and, while there are undoubtedly differences in the physical arrangements and appearance of various drives, these are usually of little consequence.
More or less 30 plus drive suppliers today in the Indian market varying from small trading companies to multinationals. However, the fact remains that there may not be more than 7 companies who can practically provide services in the board level. The reason is most of the companies who deal with AC drives are still traders or distributors having one object on sales and not on service. Also, it is a fact to notice that still the use and throw concept is not widely accepted in India. Customers always like to get the faulty drive repaired and use it as much as he can. Customers today ask for service first then product. This is the reason many of the small companies are not able to sustain in the highly competitive drive market.
The situation in which future drive users will find themselves is analogoues to that of the proud owner of a video recorder. He knows it can be set up to record his favourite soap opera every Tuesday and Friday while he is on holiday because the sales brochure says so. This means today the drives are configured for self-setting depending on customers needs of applications. Supplier however goes much further than simply choosing the most appropriate product for the job and configuring it correctly. Increasingly, users of drives are looking for complete solutions - not just the drive alone but all the components needed to make up the whole control system. There are two reasons for this shift of emphasis - convenience and compatibility. With the leaner staff levels which now are the norm in industry, few customers can afford the time and effort involved in working with multiple suppliers - there are more orders to place, more deliveries to co-ordinate and chase. And more invoices to pay.
Drive system for decentralized installation
In the past, extensive production systems have been powered, controlled and monitored from a central switchgear installation. Long rows of switch cabinets take up a lot of space and give rise to complicated cabling arrangements. Start up of the machine is complicated and time consuming due to long distances between switchgear and motors. This situation represents a cost factor that cannot be ignored in planning, installation and start up. Till recently, the Indian customers thought of having a total solution like drive, motor and gearbox together through single source with added advantage technically and commercially. So far they have seen and experienced were motor supplier, drive supplier and gearbox and accessories supplier. This has created so much of mess especially during installation and also during the system failure. During installation the customer needs to co-ordinate with three or more suppliers for solution and similarly during troubleshooting in case one of the element fail.
The switchgear, protection equipment and electronic control units are integrated into the geared motor, eliminating cabling with the motor. Standard fieldbus system has taken over the job of communicating with central controller. Multi-motor drives are connected to the power supply and the fieldbus via field distributors and system plug connections installed closely to the motors. Planning such a drive installation is now a simple procedure and definitely supports trend towards modular design and standardization of the plants mechanical components. The modular systems design simplifies the task of making subsequent modifications and additions. Flexible adaptation to all process and spatial conditions can be achieved without any difficulty. Trial installations, functional tests, transportation, installation and start up on the customers premises are much simpler and inexpensive.
Advantages of new drive systems for decentralized installations are:
- Create saving potentials for expansive production system in modular design.
· Replace centralized switchgear, protection equipment and electronic control units as well as eliminating the need for the necessary switch cabinet space.
· Reduce the amount of cabling for motors, sensors and actuators.
· Save maintenance cost.
Geared motors with integrated frequency inverter (MOVIMOT)
As it has been seen that inverters are sold as a component of the total automation and also seen integrated drives i.e. inverters and motors. Many have the opinion that it has not worked out successful due to many reasons. The recent successful introduction of MOVIMOT is not only a combination of inverter and motor but with a geared motor. It has been proved well that this is the ideal solution for many applications and industries. The MOVIMOT inverter drive represents the synthesis of an individual geared motor and a frequency inverter, which is precisely adapted to the motor. The compact drive with its infinitely variable speed only takes up slightly more space than the normal geared motor and can deliver an output torque of up to 420,000 Nm. The fully equipped drive does not take up any room on the switch cabinet. The motor cabling is restricted to carrying the supply and control voltages, creating ideal conditions for decentralized installation.
Large industrial establishments have many difficulties by having separate motor control rooms, space problems, etc. For example, most of the organizations have a separate motor control station where they install the inverters and the motors are fitted on the machine side connected through cables. Suppose the inverter trips, then the operator has to rush to the control room to identify the problem. This normally causes lot of time, money and energy. Whereas MOVIMOT does not have such limitation since it is an integration drive system.
Advantages of MOVIMOT integrated drive system are:
Available with enclosure up to IP 65 in all gear unit configurations and mounting positions as of the modular concept. A helical, worm, bevel or parallel shaft gear unit can be mounted either in foot mount or flange mount positions or else any position the customer wanted, with a choice of IP 20, IP 54, 55 or 65 depending on customers requirement. Infinitely variable speed up to 10:1 with constant torque. Most of the applications are limited within this range hence original equipment manufacturers like conveyors, construction equipment, etc will have better advantages.
· Vector oriented motor guidance. The inverters are designed on vector control technology hence reliability will be more in comparison to general inverters.
· Connection to 3 x 380 -500 V, 50/60 Hz supply voltage and 24 V DC control voltage. The MOVIMOT systems are designed to match the power requirements of 380 to 500 volts in three phase with +/- 10% variations.
· The same system can be used as general-purpose inverter also for 4 quadrant applications.
· MOVIMOT is having in built communications with the controller either via RS 485 or optional PROFIBUS, INTERBUS, AS-I and Devicenet interfaces.
· Absolutely noise free because it is housed in durable metal enclosure.
Since MOVIMOT technology is comparatively new to the Indian market, quite a lot of critical equipment manufacturers are eagerly waiting for knowing much about the technology in order to save money, time and energy.